Billy-oh

I bashed my thumb with a hammer, and it hurts like billy-oh.

Source: wiktionary

"For the wooden fence leading up to the bridge had caught fire, and it was burning like billy oh."

Source: wiktionary

"'You know—if you've ever picked the scab of a sore place. It hurts like billy-oh but it is such fun to see it coming away.'"

Source: wiktionary

"'Our old saw's as blunt as billy-oh! You couldn't cut butter with it!'"

Source: wiktionary